The present invention relates generally to methods for obtaining information regarding mineral constituent(s) of a sample, and more particularly to such methods that employ radiation scattering to derive information regarding mineralization of a sample.
Nature synthesizes hierarchical, self-assembled, organic/biomineral complex composites under ambient conditions with superior mechanical properties. In general, biomineralization can be divided into two categories: biologically induced mineralization in which an organism modifies its local microenvironment to establish conditions suitable for the chemical precipitation of extracellular mineral phases, and boundary organized biomineralization in which inorganic particles are grown within or on a matrix generated by an organism. While biologically induced mineralization can typically result in mineral particles with a broad size distribution and without a unique morphology, boundary organized biomineralization can provide better control over size, morphology and crystallographic orientation of the mineralized particles. In either case, the central tenet in the regulation of mineral deposition in biological systems is that organic matrices control the nucleation and growth of inorganic structures. Such control can be exerted through the use of organic macromolecules that can provide nucleation sites and dictate crystal orientation and morphology. However, these processes are not well understood.
Human bones and teeth are examples of bio-mineralized tissues that are formed by the deposition of hydroxyapatite on aligned collagen fibers. Hydroxyapatite formation and deposition is a key element for bone defect repair. The human body is able to repair minor injuries of bones, but such natural repair mechanisms typically do not work efficiently in case of large injuries or damaged self-reconstruction. In such cases, autografts and allografts may be used for the replacement of the damaged part. But autografts and allografts have certain drawbacks. For example, autografts can be limited by the availability of the size of usable bone and allografts can carry risks of disease transfer, infections and adverse immunological response. As such, the fabrication and use of bone tissue and implant has been an active area of research. Biomaterial scaffolds are used as three-dimensional extracellular matrices to engineer bone tissue and bone implant. For example, silk is one of the most promising scaffolding materials for tissue engineering due to its biocompatibility and advantageous mechanical properties. To have a better control over the functionality of engineered bone, tools for studying the mineralization process are needed.
Scanning electron microscopy (SEM) has been traditionally used as a characterization technique to study the detailed surface topography and crystal morphology of the mineral deposits. However, SEM is an invasive technique, as are most of the other commonly used methods to study mineralized samples, such as X-ray diffraction, X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). As such, these techniques are not particularly suited for time-dependent measurements at different mineralization stages of a sample under study.
Fourier transform infrared (FTIR) spectroscopy is a non-invasive technique that has been used for molecular characterization of mineral samples. But it lacks the ability to provide morphological information. Further, its use is generally limited in samples having a high water content, such as biological tissue.
In biomedical imaging for bone formation, micro computed tomography or X-ray analysis are most often employed to assess bone density and mineral distribution. These techniques, however, lack the resolution typically needed to understand fine control of mineralization. Nor do they provide sufficient sensitivity to assess early stages of mineralization.
Hence, there is a need for enhanced methods for monitoring and quantifying mineralization processes.